Twelve jurors failed to agree on a death sentence for Colorado cinema shooter James Holmes, prompting shocked sobs from victims, police officers and his own mother.

Holmes will instead spend the rest of his life in prison for fatally shooting 12 people.

The nine women and three men said they could not reach a unanimous verdict on each murder count.

That automatically eliminates the death penalty for Holmes, who blamed the killings on mental illness.

The verdict came as a surprise. The same jury earlier rejected Holmes' insanity defence, finding him capable of understanding right from wrong when he carried out the 2012 assault that injured 70.

Jurors also previously moved closer to the death penalty when they quickly determined the severity of Holmes' crimes outweighed his mental illness.

As the sentence was read, Holmes' mother, Arlene, who had asked the jury to spare her son's life, leaned her head against her husband's shoulder and began sobbing.

Tears broke out across the courtroom. At the back, Aurora police officers who responded to the bloody scene of Holmes' attacks began crying.

Sandy Phillips, whose daughter Jessica Ghawi was killed by Holmes, shook her head no and then held it in her hands.

Ashley Moser, whose six-year-old daughter died in the attack and who was herself paralysed by Holmes' bullets, also shook her head and then slowly leaned it against the wheelchair of another paralysed victim, Caleb Medley.

Families of victims began to leave the courtroom as Judge Carlos Samour continued reading the verdict. Their wails were audible through the closed courtroom doors.

As in previous proceedings, Holmes, who is on anti-psychotic medication that dulls his responses, showed no reaction.

One juror told reporters outside court that there was a single juror who refused to give Holmes the death penalty and two others who were wavering. The key issue was Holmes' mental illness.

Prosecutors argued Holmes deserved to die because he methodically planned the attack at a midnight screening of a Batman film, even blasting techno music through earphones so he would not hear his victims scream.

The defence argued Holmes' schizophrenia led to a psychotic break, and powerful delusions drove him to carry out one of the nation's deadliest mass shootings.

Jurors deliberated for about six and a half hours over two days before deciding on Holmes' sentence.

The verdict is the latest setback for the death penalty in Colorado, which has executed only one person since the US Supreme Court reinstated the penalty in 1977.

There was never any question during the gruelling, four-month trial as to whether Holmes was the killer.

He meekly surrendered outside the cinema, where police found him clad head-to-toe in combat gear.

The trial hinged instead on the question of whether a mentally ill person should be held legally and morally culpable for an act of unspeakable violence.

It took jurors only about 12 hours of deliberations to decide the first part - they rejected his insanity defence and found him guilty of 165 counts.

The defence then conceded his guilt, but insisted during the sentencing phase that his crimes were caused by the psychotic breakdown of a mentally ill young man, reducing his moral culpability and making a life sentence appropriate.

The jury's final decision came after days of tearful testimony from relatives of the victims.

The case could have ended the same way more than two years ago, when Holmes offered to plead guilty if he could avoid the death penalty.

Prosecutors rejected the offer. But the victims and the public might not have ever learned in detail what was behind the shootings had the plea deal been accepted.

The trial - featuring a journal where Holmes had secretly described his murderous plans - provided a rare look inside the mind of a mass shooter.

Most are killed by police, kill themselves or plead guilty. By pleading insanity, he dropped his privacy rights and agreed to be examined by court-ordered psychiatrists. Holmes told one that he had been secretly obsessed with thoughts of killing since he was 10.

His parents testified that he seemed a normal, affectionate child who withdrew socially in adolescence and became fascinated with science but did not seem abnormal.

Holmes studied neuroscience hoping to understand what was happening to his mind. But it was when he moved from San Diego to Colorado to attend graduate school that his meltdown accelerated.

Holmes dropped out of his prestigious doctoral programme at the University of Colorado and broke up with a fellow student, the only girlfriend he had ever had.

He began to buy guns and thousands of rounds of ammunition and scouted out The Century 16 cinema complex to learn which auditorium would offer the highest number of victims.

Holmes also constructed an elaborate booby-trap in his flat a few miles away. It failed to explode, but it was designed to blow up and divert police and firefighters at the precise moment of his calculated attack.

Four mental health experts testified that the shooting would not have happened if Holmes were not severely mentally ill. He was having increasingly palpable delusions that killing others would increase his own self-worth, forensic psychiatrist Jeffrey Metzner said.

Shortly after midnight on July 20, 2012, he slipped into the premiere of The Dark Knight Rises, stood before the capacity crowd of more than 400 people, threw gas canisters, and then opened fire with a shotgun, assault rifle and semi-automatic pistol.

Your Comments

COMMENT RULES: Comments that are judged to be defamatory, abusive or in bad taste are not acceptable and contributors who consistently fall below certain criteria will be permanently blacklisted. The moderator will not enter into debate with individual contributors and the moderator’s decision is final. It is Belfast Telegraph policy to close comments on court cases, tribunals and active legal investigations. We may also close comments on articles which are being targeted for abuse. Problems with commenting? customercare@belfasttelegraph.co.uk